1) Field of the Invention
The invention relates to a hydraulic valve having a valve body in a valve housing, which has a first, a second and a third cutout. A hydraulic medium can be fed via the first cutout. In addition, the hydraulic medium can be fed to a pressure consumer via the second cutout and the hydraulic medium can be fed to a pressure sink via the third cutout. The valve body can move to and fro between two end positions, in which case, in the first end position, the hydraulic medium passes from the first to the second cutout, and, in the second end position, the hydraulic medium passes from the second to the third cutout.
2) Description of Related Art
Such hydraulic valves are generally known and are also referred to as changeover valves. In this case, the changeover takes place by the valve body moving to and fro, which takes place comparatively rapidly. This may result in undesirable pressure surges in the hydraulic system if the flow cross sections for the hydraulic medium are released comparatively rapidly by the valve body. Depending on the design of the hydraulic system, such pressure surges may cause oscillations in the overall system which are likewise undesirable.
It has been shown, for example, that, when using two-stage changeover valves in hydromechanical spring-energy store drives for high-voltage switchgear assemblies, the pressure surges in the hydraulic system may be so great that the drive and/or the switch are influenced thereby.